This invention relates to miter saws.
Typical miter saw apparatus comprises a table having a flat horizontal bed and a vertical back that acts as a stop for the workpiece that is to be sawed. The back has a central opening through which a saw blade may pass for making a cut. Usually an arm is mounted beneath the table bed for swinging in a horizontal plane about a vertical axis. Post members that project upright from this arm at the front and rear of the table are provided with vertically movable guide members which are slotted for the blade of the saw to slide through and constrained to move back and forth in a nominally vertical plane. A user of mitering apparatus having these general characteristics often experiences a binding effect between the saw blade and its guide slots. Binding results primarily from the inability of the user to maintain perfect colinearity between the line of action on which the force is applied to the saw handle and the line of action of the saw blade. In other words, although it is the intention of the user to move his hand, the saw handle and the blade strictly longitudinally or linearly, sideways and torsional forces are usually developed which cause the saw blade to twist and bind in its guides. The problem is often more acute in sophisticated miter apparatus designs wherein guide tolerances are small and the size of the saw is large so that torsional or bending forces are amplified by the relatively long moment arm between the saw blade and the line of action of the handle. Moreover, since the joints in the wrist, elbow and shoulder of the human arm are not constrained to move together perfectly linearly, the natural tendency is to twist the saw about its longitudinal axis. This results in a counterforce being developed by the twisted saw and its frame which must be resisted by development of transverse forces in the joints which results in the user's arm being stressed and fatigued when an extended sawing operation is being carried out.